Reaction Times

A series of tests of reaction times to determine which ones require what out of us, and hopefully allow a study of which parts correlate with intelligence best.

Reaction times are the tip of the intelligence sword. Not only do basic reaction times correlate with general intelligence, more complicated situations cause the correlations to go up. Intelligence itself is a curious topic but the thing that really gets me about reaction times is that they might be the useful-in-life-or-death-scenarios part of being smart, which leaps it straight to the top of my list of things I should learn a lot about. 

But there’s a lot we don’t know, like why the correlation between reaction time and intelligence diminishes for tasks where the reaction times are greater than about one second. And it makes sense that, for extremely simple stimulus-response challenges, the correlation is weaker as well. But somewhere in that range, there is work the brain is doing, and the speed at which it works is a fair measure for how well it works in scenarios without any sort of time constraint or measurement. 

So I thought I’d answer some questions for myself, and help other people get the more complicated answers. For instance, how do increasingly complex responses change reaction time? What about requiring a simple calculation? What about dropping the requirement for information to cross the corpus callosum by showing the information required for the response to the eye matching the arm giving the response (compared to the opposite)? Does a changing context for the test impact reaction times? What precisely is happening in the brain to generate these reactions?

For example, if there’s a large difference in reaction times between two similar tests, where it shows the key you must hit, either a ‘g’ or a ‘j’, but in one test the letters are always shown in the center of the screen and in another test ‘g’ is always on the right and ‘j’ is always on the left, that indicates that distinguishing the two letters may be important. But if the second test is substantially different from one where ‘g’ is on the left and ‘j’ is on the right (and your hands rest so ‘g’ is hit with the left hand and ‘j’ with the right) then intra-brain communication may be a critical delay. And what a useful thing to know that would be! Recognizing shapes is complex pattern matching – correlating with intelligence makes sense. But to what extent is raw in-brain communication speed a factor? And for which tests are the IQ correlations strongest and weakest?

I’m very curious and I hope you are too. I’m not tracking the data right now (it’s saved locally to your computer), but please use for your own amusement and edification. If anyone wants to shell out for a proper population-based study, get in touch, collection and handling of this data should be done sensitively.